Joint Spatial–Temporal Channel Modeling for Underwater Wireless Optical Links

In underwater wireless optical communications (UWOC), channel model is crucial for system design and performance evaluation. The absorption and scattering of seawater may lead to energy loss and direction change of photons, introducing dispersion in both time and space domains, which complicates channel modeling. There have been many studies on single domain channel modeling, but few consider the joint modeling of time and space domains, especially in multiple-input multiple-output (MIMO) scenarios. In this paper, we consider UWOC MIMO links and propose a weighted delay exponential polynomial (WDEP) to model the joint spatial-temporal response of general UWOC MIMO links with arbitrary numbers of light sources and receivers. Numerical results show that the proposed WDEP model fits well with the Monte Carlo simulation results of UWOC MIMO links in turbid water environments including harbor water and coastal water.